1. Field
Example embodiments relate to a method of transferring carbon nanotubes, and more particularly, to a method of transferring carbon nanotubes oriented in a vertical direction to a particular location in a horizontal direction.
2. Description of the Related Art
Carbon nanotubes may be used in many fields, e.g., electron emission sources, actuators, electrodes of fuel cells, gas separation films, sensors, energy storages, and transistors. When the carbon nanotubes are used in these fields, the carbon nanotubes may be oriented in one direction. However, arranging the carbon nanotubes in a desired direction may be difficult. For example, in manufacturing a transistor in which the carbon nanotubes are used as a channel, one of the largest technical obstacles may be whether the carbon nanotubes are formed to a desired length. Other obstacles may include whether the carbon nanotubes are located in a desired position or whether the carbon nanotubes are oriented in a desired direction or not.
At least two methods of forming carbon nanotubes are available for forming carbon nanotubes utilized in a field effect transistor (FET). The first method grows the carbon nanotubes from a catalyst on a substrate. The second method coats a dispersion solution, which may be made by adding powders of the carbon nanotubes into a solvent, on a substrate.
In the direct growing method, the location and length of the carbon nanotubes may be controlled by controlling the position of the catalyst and growing time while growing the carbon nanotubes. However, controlling the growing direction of the carbon nanotubes still remains a difficult task. Recently, a report has been disclosed that the orientation direction of the carbon nanotubes growing on a quartz substrate may be affected by the crystal direction of the substrate. However, this method may hardly be applied to other substrates.
In the dispersion the dispersion method, a dispersion solution may be coated on a substrate and the carbon nanotubes generally form a network with random directionality, so controlling the direction of the carbon nanotubes may be difficult.